Multiple speed hydraulic control system

ABSTRACT

A MULTIPLE SPEED HYDRAULIC STERING CONTROL SYSTEM FOR A TRACTOR LOADER VEHICLE WITH MEANS RESPONSIVE TO A LOW SPEED ENGINE THROTTLE SETTING TO DIRRECT A HIGH RATE OF FLUID FLOW TO THE CONTROL SYSTEM AND RESPONSIVE TO A HIGH SPEED THROTTLE SETTING TO DIRECT A LOW RATE OF FLUID FLOW TO THE CONTROL SYSTEM. A MULTIPLE SPEED HYDRAULIC STEERING AND LIFTING CONTROL SYSTEM FOR A TRACTOR LOADER VEHICLE WITH MEANS RESPONSIVE TO A LOW SPEED ENGINE THROTTLE SETTING TO DIRECT FLUID FLOW FOR STEERING AND LIFTING, RESPECTIVELY, AT ONE DISPROPORTIONATE RATE AND RESPONSIVE TO A HIGH SPEED ENGINE THROTTLE SETTING TO DIRECT FLUID FLOW FOR STEERING AND LIFTING, RESPECTIVELY, AT A DIFFERING DISPPROPORTIONATE RATE. SPECIFICALLY, STEERING RECEIVES ITS HIGH RATE OF FLUID FLOW AT LOW ENGINE SPEED AND LIFTING RECEIVES ITS HIGH RATE OF FLUID FLOW AT HIGH ENGINE SPEED, WITH EACH HAVING AVAILABLE AT LEAST SOME FLOW FULL TIME.

A ril 11, 1972 R. F. ZIMMERMAN Re. 27,334

MULTIPLE SPEED HYDRAULIC CONTROL SYSTEM Original Filed Feb. 55, 1966ENGINE 73 76 THROTTLE CONTROL United States Patent 27,334 MULTIPLE SPEEDHYDRAULIC CONTROL SYSTEM Richard F. Zimmerman, Waukegan, 11L, assignorto International Harvester Company Original No. 3,360,925, dated Jan. 2,1968, Ser. No.

524,894, Feb. 3, 1966. Application for reissue June 2, 1969, Ser. No.848,756

Int. Cl. Fb 11/16, 15/18 US. Cl. 60-19 10 Claims Matter enclosed inheavy brackets [II appears in the original patent but forms no part ofthis reissue specification; matter printed in italics indicates theadditions made by reissue.

ABSTRACT OF THE DISCLOSURE [A multiple speed hydraulic steering controlsystem for a tractor loader vehicle with means responsive to a low speedengine throttle setting to direct a high rate of fluid flow to thecontrol system and responsive to a high speed throttle setting to directa low rate of fluid flow to the control system] A multiple speedhydraulic steering and lifting control system for a tractor loadervehicle with means responsive to a low speed engine throttle setting todirect fluid flow for steering and lifting, respectively, at onedisproportionate rate and responsive to a high speed engine throttlesetting to direct fluid flow for steering and lifting, respectively, ata diflering disproportionate rate. Specifically, steering receives itshigh rate of fluid flow at low engine speed and lifting receives itshigh rate of fluid flow at high engine speed, with each having availableat least some flow full time.

Summary of the invention This invention relates to steering andimplement control systems for tractor loader vehicles and moreparticularly relates to multiple speed hydraulic steering and implementcontrol systems for such vehicles wherein engine speed regulates thesteering and implement speeds.

In a tractor loader vehicle incorporating hydraulic power steering it isoften desirable to provide a multiple speed steering control system.Such a system will afford fast steering control at a low vehicle speedand slow steering control at a high vehicle speed. The fast steeringcontrol is required throughout the digging and loading cycles at lowvehicle speeds. Under such conditions the faster control results inquick and accurate maneuvering. On the other hand a slow steeringcontrol is required where the vehicle is operating at a high rate ofspeed, such as movement between loadin sites or during on-highwaytravel. The slower steering produces better steering feel and ensuresoperating safety under such conditions.

It is also desirable to coordinate the implement speed control with thevehicle or engine speed. Thus at low engine speeds a slow implementspeed utilizes the maximum power output from the hydraulic pumps whileat high engine speeds at high implement speed results in faster cyclingof the implement, such as during cycling between the dumping and diggingpositions.

Accordingly it is an object of the present invention to provide amultiple speed hydraulic steering control systern for a tractor loadervehicle incorporating means responsive to Low engine speeds to direct ahigh rate of fluid flow to the steering control circuit and responsiveto high engine speeds to direct a low rate of fluid flow to the steeringcontrol circuit.

Another object is to provide a multiple speed control system for atractor loader vehicle in which first and Re. 27,334 Reissued Apr. 11,1972 second sources normally supply fluid under pressure to the steeringand implement control circuits, respectively, in which a third source offluid under pressure directs fluid to the steering control circuit forfast steering control and slow implement control during a low throttlesetting of the vehicle engine, and in which the third source directsfluid to the implement control circuit for slow steering control andfast implement control during a high throttle setting of the engine.

Still another object is to provide a multiple speed control system for atractor loader vehicle in which a twoway valve operates responsive to alow throttle setting of the vehicle engine to direct a high rate offluid flow to the hydraulic steering control valve and a low rate of[fluid flow to the implement control valve, and in which the two wayvalve further operates responsive to a high throttle setting of theengine to direct a low rate of fluid flow to the steering control valveand a high rate of fluid flow to the implement control valve.

Other objects and advantages of the present invention will becomeapparent to those skilled in the art when the following specification isread in conjunction with the ac companying drawings, wherein.

Description of the drawings FIGURE 1 is a side elevational view of atractor loader vehicle of the articulated frame section designincorporating features of the present invention; and

FIGURE 2 is a top plan view of portions of the tractor loader of FIGURE1 showing the multiple speed steering control system and relatedelements in a superimposed schematic diagram.

Description of the preferred embodiment Referring now to the drawingsand particularly FIG- URE l, the numeral 10 designates an articulatedframe tractor loader vehicle. The vehicle 10 comprises a front framesection 12 pivotally connected to a rear frame section 14 about anupright axis. The rear frame 14 supports the vehicle engine [(notshown)] while the front frame section 12 supports an implement, such asthe loader bucket 16 pivotally mounted on the pair of lift boom arms 18.The lift boom arms are raised and lowered through operation of a pair oframs 20 while the attitude of the bucket is controlled through operationof ram 22 and conventional rocker arm linkage 24 mounted between theboom arms.

Steering of the vehicle 10 is effected through operation of a pair ofhydraulic rams 26 and 27 pivotally connected at their head ends to thefront frame 12 and at their nod ends to the rear frame 14.

Referring now to FIGURE 2, the frame sections 12 and 14 of the loadervehicle are shown in phantom view. The steering control system of thepresent invention is illustrated in a superimposed schematic diagramwith the respective elements thereof shown in relationship to the framesections of the vehicle. The power take-off 28 is mounted on the rearframe section 14 and is driven by the vehicle engine [(not shown)]. Thepower take-off 28 drives a hydraulic pump 30 which receives fluid fromreservior 32 through conduit 34 and delivers fluid under pressurethrough conduit 36 into conduit 38 and steering control valve 40.

The steering control valve 40 may be of a conventional spool-typeconstruction and operates in response to manipulation of steering wheel41 to deliver fluid under pressure through conduits 42 and 44 to extendram 27 and retract ram 26 for a right-hand steering movement, and todeliver fluid under pressure into conduits 46 and 48 to retract ram 27and extend ram 26 for a left-hand steering movement. Return fluid fromvalve 40 is delivered through conduit 50 into reservoir 32.

The power take-off 28 further drives a dual hydraulic pump whichpreferably comprises a pair of vane elements 52 and 54 mounted on acommon shaft. The pump element 52 receives fluid from reservoir 32through conduit 56 and delivers fluid under pressure through conduit 58into conduit 60 and loader control valve 62. The loader control valve 62is conventional and is manipulated by the operator to control theoperation of boom rams 20 and bucket ram 22 by delivering fluid to suchrams through appropriate conduits [(not shown)]. Pump elements 52 thussupplies a continuous source of fluid pressure for operation of thebucket or implement.

Pump element 54 withdrawn fluid from reservoir 32 through conduit 56 anddelivers fluid under pressure through conduit 64 into two-way valve 66.The valve 66 is conventional in construction and incorporates a spoolelement 68 slidable between first and second positions to direct fluidfrom conduit 64 into either of the conduits 38 or 60. With the spoolelement 68 in the first (lower) position, as illustrated in FIG. 2,fluid from pump element 54 is directed into conduit 38 and combined withfluid from pump 30 for delivering into steering control valve 40. Withthe spool element 68 in the second (upper) position fluid from pumpelement 54 is directed into conduit 60 and combined with fluid from pumpelement 52 for delivering into loader control valve 62. The valve 66 maybe constructed to deliver a metered amount of flow to the conduits 38and 60 depending on the extent of travel of spool 68 between its extremepositions. Thus with spool 68 moved to its fully down position a maximumamount of fluid would be delivered into conduit 38 and a minimum amountof fluid would be delivered into conduit 60. As spool 68 moves upward, adecreasing amount of fluid would be delivered into conduit 38 with anincreasing amount of fluid delivered into conduit 60 depending on theextent of travel of the spool.

The two-way valve 66 is controlled through operation of throttle linkage70. The linkage 70 comprises control link 72 which is connected at oneend to throttle control 73 of the vehicle engine and at its other end toan arm of bellcrank lever 74 which is mounted on rear frame 14. A link76 operably connects bellcrack 74 with the spool 68. A flexible cable 78is connected at one end to a depending arm of bellcrak 74 and at itsother end to an arm of bellcrank 80 which is mounted on the front frame12. The flexible cable 78 permits throttle control between the framesections throughout articulated steering movements. The angularpositions of the bellcrank 74 and 80 are controlled through operatormanipulation of foot lever 82 by means of a link 84 interconnectinglever 82 with an arm of bellcrank 80.

With the foot lever 82 in the lower speed position, as illustrated inFIG. 2, the throttle linkage 70 will eflect a low speed throttle settingof the engine and simultaneously operate the spool 68 of valve 66 intothe first or lower position shown in the drawing. The two-way valve 66will now operate to combine flow from pump element 54 with flow frompump 30 to produce a high flow rate into steering control valve 40. Thiswill result in fast steering operation of rams 26 and 27 during lowengine speeds. At this time the loader control valve 62 is suppliedsolely by pump element 52 for low speed operation of the implement.

With the foot control 82 in the high speed position the throttle linkage70 will affect a high speed throttle setting of the engine whilesimultaneously operating spool 68 of valve 66 into the second or upperposition. Flow from pump element 52 will now be combined with flow frompump 54 to produce a high flow rate into loader control valve 62 forhigh speed operation of boom rams 20 and bucket ram 22. With the valve66 in this position only fluid from pump 30 is delivered into steeringcontrol valve 40 for low speed steering operation.

It is apparent that applicant has provided a multiple speed hydrauliccontrol system which coordinates steering and implement control inrelationship to engine throttle setting. Thus at a low throttle settinga high rate of fluid flow is directed to the steering rams for faststeering while a low rate of fluid flow operates the implement rams. Ata high throttle setting applicant's invention provides low speedsteering and high speed implement control.

It will be understood that various changes in the details andarrangement of parts, which have been described and illustrated in orderto explain the nature of the invention, may be made by those skilled inthe art within the principle and scope of the invention as expressed inthe appended claims.

What is claimed is:

I. In a multiple speed hydraulic control system for a tractor loadervehicle driven by an engine and having hydraulic steering and implementmotors, the combination of: first means to supply fluid under pressureto the steering motor; second means to supply additional fluid underpressure; valve means operable in a first position to fluid- 1y connectthe first and second means in parallel flow for high speed operation ofthe steering motor; and, control means for varying the speed of theengine between maximum and minimum values, the control means furtheroperating the valve means to the first position responsive to asubstantially minimum engine speed.

2. A multiple speed hydraulic control system as defined in claim 1wherein: the control means includes linkage means for selectivelyvarying the throttle setting of the engine between maximum and minimumvalues, the linkage means further being connected to operate the valvemeans to the first position responsive to a substantially minimumthrottle setting.

3. A multiple speed hydraulic control system as defined in claim 1 andfurther including: third means to supply fluid under pressure to theimplement motor; the valve means being operable to a second position bythe control means responsive to a substantially maximum engine speed tofluidly connect the second and third means in parallel how for highspeed operation of the implement motor.

4. A multiple speed hydraulic control system as defined in claim 3wherein: the control means includes linkage means for selectivelyvarying the throttle setting of the engine between maximum and minimumvalues, the linkage means further being connected to operate the valvemeans to the first and second positions responsive to substantiallyminimum and maximum throttle settings, respectively.

5. A multiple speed hydraulic control system as defined in claim 3wherein: the valve means includes a spool operable with the valve in thefirst position to direct fluid from the second means to the steeringmotor, and with the valve in the second position to direct fluid fromthe second means to the implement motor.

6. A multiple speed hydraulic control system as defined in claim 5wherein: the control means includes an operator controlled throttlelinkage operably connected with the throttle of the engine, and acontrol link operably connecting the throttle linkage with the spool,the link being sized and arranged to operate the valve to the firstposition with the throttle at a low setting and to the second positionwith the throttle at a high setting.

7. Procedure for hydraulic speed control in a power driven, powersteered, material lifting vehicle, which vehicle has means of poweroperation comprising a first output flow to steering and a second outputflow to lifting, said procedure comprising the steps of:

separately providing first actuation when the vehicle power drive hasone setting and second actuation when the vehicle power drive has adifferent setting; supplying to steering the combined output of saidfirst flow and an independent flow in response to the first actuation;and

supplying to lifting the combined output of said second and independentflows in response to the second actuation, so as to accomplish steeringof the vehicle at a high rate of operation as the vehicle is drivenalong at one drive setting and so as to accomplish material lifting ofthe vehicle at a high speed of operation as the vehicle is driven alongat a difierent setting.

communication between the second pump (52) and the implement circuit;and

(f) a control (68) systematically controlled along with the enginerunning speed whereby the control and speed are kept at points incorrespondence with one another, and efiective (I) for connecting thethird pump with the steering circuit when the engine is run below afirst predetermined speed;

(2) for diverting a progressively increasing portion of the output ofthe third pump to the implement circuit when the engine is acceleratedfrom said first speed to a second predetermined speed; and

(3) for disconnecting the third pump from the steering circuit when theengine while running at the second speed is accelerated thereabove.

8. Procedure for the coordinated operation of a power steered,self-driven, material loading vehicle having an engine, and pluralhydraulic pumps including one pump solely for steering and another pumpsolely for lifting, said procedure comprising the steps of:

producing a demand for one setting of the vehicle drive; If

separately producing a demand for a differing setting of the vehicledrive;

supplying all the time the output of one pump and supplying some timethe combined output of two of the pumps to steering, the time of saidcombined output 20 occurring when the demand is for one drive setting;and

supplying all the time the output of another pump and supplying at acertain time the combined output of two of the pumps to lifting, thecertain time of the just said combined output occurring when the demandis for a difi'ering drive setting, so that the steering of the vehicleis accomplished as a high speed operation as the vehicle is driven alongat some time and ma- References Cited The following references, cited bythe Examiner, are of record in the patented file of this patent or theoriginal tert'al loading of the vehicle is accomplished as a high tspeed operation as the vehicle is driven along at a cer- UNITED STATESPATENTS tain time. 9. The invention of claim 8, the one drive settingchar- 5 3; Henry 60 52 acterized by a low engine speed and the difieringsetting 3258926 1 2 Schuitz et a1 60 52 characterized by a high enginespeed, insuring the required 3355994 12/1967 gf 5 2;

fast steering control when quickly and accurately maneuvering thevehicle during its slow rate of speed and insuring the required slowsteering control during transport of the vehicle at its high rate ofspeed.

10. An integrated hydraulic system for a vehicle having 4 a controlledpropulsion engine comprising:

EDGAR W. GEOGHEGAN, Primary Examiner 0 US. Cl. X.R.

60-52 HE, 52 S; 914l3

